Conventionally, a waste heat recovery system is known for recovering waste heat from supercharged air supplied to an engine from a supercharger. For example, Japanese Unexamined Patent Publication No. 2011-149332 discloses a waste heat recovery power generation device provided with an air cooler which cools compressed air supplied from a supercharger to an engine, a second waste heat recovery device, an evaporator, a turbine, a power generator connected to the turbine, and a condenser. The air cooler cools compressed air supplied to an engine from a supercharger, by a cooling medium which flows inside a first heat transfer pipe after being cooled by a cooling medium flowing inside a second heat transfer pipe. The second waste heat recovery device heats a heating medium by the waste heat recovered from the compressed air in the air cooler. The evaporator evaporates an organic fluid by exchanging heat between the heating medium and the organic fluid. The turbine expands the organic fluid which has flowed out from the evaporator. The condenser condenses the organic fluid which has flowed out from the turbine. Pure water or seawater is supplied to the first heat transfer pipe of the air cooler, as a cooling medium for cooling the compressed air. Furthermore, seawater is supplied to the condenser as a cooling medium for cooling the organic fluid.
In the waste heat recovery power generation device disclosed in Japanese Unexamined Patent Publication No. 2011-149332, the supply of a cooling medium (pure water or seawater) to the first heat transfer pipe of the air cooler and the supply of a cooling medium (seawater) to the condenser are carried out respectively by independent supply lines. Therefore, pumps are required respectively in each of the supply lines, and the structure is complicated.